The present invention relates to an improved tobacco treating process and more particularly to an improved process for expanding tobacco wherein the tobacco is maintained at a relatively high moisture content.
A number of processes are known in the art wherein tobacco is expanded by firstly impregnating the tobacco with an expanding agent which may be a gas, such as carbon dioxide under pressure. The impregnated tobacco is then subjected to further treating, usually heat, whereby the expanding agent and the moisture in the tobacco are driven off and the resulting tobacco product is left in an expanded condition. For example, U.S. Pat. No. 4,336,814, issued to Larry M. Sykes et al on June 29, 1982, and No. 4,340,073, issued to Roger Z. de la Burde et al on July 20, 1982, as well as a number of the earlier patents and publications noted therein, teach or suggest such broad process. In addition, a number of patents and patent applications are known in the art which teach structural arrangements for carrying out the process of expanding impregnated tobaccos in duct systems and associated drying chambers such as U.S. Pat. No. 3,357,436, issued on Dec. 12, 1967 to A. H. Wright; U.S. Pat. No. 3,786,573, issued on Jan. 22, 1974 to John J. Scheppe and Raymod N. Carini; U.S. Pat. No. 4,366,825, issued on Jan. 4, 1983 to Frank V. Utsch et al; as well as a number of the earlier patents noted therein. Further, U.S. Pat. No. 4,494,556, issued on 22 Jan. 1985 and U.S. Pat. No. 4,528,995, issued on 16 July 1985, each disclose structural arrangements that can be used for expanding impregnated tobaccos in duct systems and communicating drying chambers, each further teaching a tobacco feed device located substantially at the entrance of a separator device for introducing tobacco to be dried and expanded into the duct at the entrance to the separator device.
The present invention recognizing certain deficiencies in past processes for expanding tobacco, provides an improved process for expanding tobacco with decreased tobacco filling power loss and concommitant decreases in losses of glycerine, alkaloids and sugar. In addition, the process of the present invention provides a decrease in exit dryer tobacco temperature while achieving high particle expansion and increased exit dryer tobacco moisture with resulting larger and less friable particles. With the increased exit dryer tobacco moisture as a result of the present invention little, if any, reordering is required to bring the expanded tobacco product to the final desired moisture content and less cooling and accordingly, less energy is required to bring the exit tobacco product to an acceptable storage temperature. Further, since little or no tobacco reordering is required to bring the expanded product to final desired moisture, little or no water is required to be added and, as a consequence, filling power loss is much decreased.
Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein.